The present invention relates to a device for measuring the ultra-violet (hereinafter called UV) radiation in the UV-A range and in the UV-B range and to a method for manufacturing this device.
UV radiation meters are intended either to prevent persons from a too long and thus harmful influence of erythem-effective radiation, on the one hand, during a sun bath or a mountain tour, i.e., during a natural irradiation, and on the other hand, during an artificial irradiation from so-called solaria or home UV radiators, or to indicate the suited irradiation duration for therapy purposes. In the recent time there have become known, especially by the applicant, devices for measuring either the erythem-effective radiation intensity (U.S. Pat. No. 3,851,970) or the already received dose (U.S. application Ser. No. 440,579). The manufacture of such measuring devices is based on the natural sun light or on a well determined artificial UV source. With the aid of a filter combination a predetermined wavelength range is cut out from the sun light spectrum or from the spectrum of the artificial UV source and then the scale of the measuring device can be calibrated in microwatts per square centimeter. But it is to be noted that the wave length range results from the cooperation of the filter combination with the measuring cell so that after a change of the measuring cell perhaps another filter combination has to be chosen. There are many different radiators on the market having different line intensities. These different line intensities cause within the effective wave length range defined by the filters and the measuring cell different irradiation durations or erythem thresholds, respectively. It is therefore necessary to calibrate the UV radiation measuring devices for the natural light and for the different artificial UV radiators.